Golf club head

ABSTRACT

A hollow golf club head with a concave portion is disclosed and claimed. The club head includes a metallic portion and a light-weight portion, which may be formed of plastic, composite, or the like. The concave portion allows the club designer to make a club head having very thin portions while still maintaining the requisite structural integrity. Convex bulges may optionally be provided to house weight inserts to enhance the playing characteristics of the golf club. The metallic portion of the club head may take on the appearance of a frame, into which several light-weight inserts are positioned. These light-weight inserts may be positioned in the crown, skirt, and sole of the club head. The club head may be formed by co-molding, eliminating the need for welding or adhesives, freeing mass to be used in more beneficial ways. The club head may be large to increase playability and forgiveness.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation-in-part of U.S. patent application Ser. No.11/363,098 filed on Feb. 28, 2006, now pending, which is 1) acontinuation-in-part of U.S. patent application Ser. No. 11/110,733filed on Apr. 21, 2005, now pending, and 2) a continuation-in-part ofU.S. patent application Ser. No. 11/180,406 filed on Jul. 13, 2005, nowpending. Each of these documents is incorporated herein by reference inits entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a golf club, and, more particularly,the present invention relates to a large wood-type golf club head withimproved physical attributes.

2. Description of the Related Art

Golf club heads come in many different forms and makes, such as wood- ormetal-type (including drivers and fairway woods), iron-type (includingwedge-type club heads), utility- or specialty-type, and putter-type.Each of these styles has a prescribed function and make-up. The presentinvention primarily relates to hollow golf club heads, such as wood-typeand utility-type (generally referred to herein as wood-type golf clubs).

Wood-type type golf club heads generally include a front or strikingface, a crown, a sole, and an arcuate skirt including a heel, a toe, anda back. The crown and skirt are sometimes referred to as a “shell.” Thefront face interfaces with and strikes the golf ball. A plurality ofgrooves, sometimes referred to as “score lines,” may be provided on theface to assist in imparting spin to the ball and for decorativepurposes. The crown is generally configured to have a particular look tothe golfer and to provide structural rigidity for the striking face. Thesole of the golf club contacts and interacts with the ground during theswing.

The design and manufacture of wood-type golf clubs requires carefulattention to club head construction. Among the many factors that must beconsidered are material selection, material treatment, structuralintegrity, and overall geometrical design. Exemplary geometrical designconsiderations include loft, lie, face angle, horizontal face bulge,vertical face roll, face size, sole curvature, center of gravity, andoverall head weight. The interior design of the club head may betailored to achieve particular characteristics, such as by includinghosel or shaft attachment means, perimeter weighting on the face or bodyof the club head, and fillers within hollow club heads. Club headstypically are formed from stainless steel, aluminum, or titanium, andare cast, stamped as by forming sheet metal with pressure, forged, orformed by a combination of any two or more of these processes. The clubheads may be formed from multiple pieces that are welded or otherwisejoined together to form a hollow head, as is often the case of clubheads designed with inserts, such as sole plates or crown plates. Themulti-piece constructions facilitate access to the cavity formed withinthe club head, thereby permitting the attachment of various othercomponents to the head such as internal weights and the club shaft. Thecavity may remain empty, or may be partially or completely filled, suchas with foam. An adhesive may be injected into the club head to providethe correct swing weight and to collect and retain any debris that maybe in the club head. In addition, due to difficulties in manufacturingone-piece club heads to high dimensional tolerances, the use ofmulti-piece constructions allows the manufacture of a club head to atight set of standards.

It is known to make wood-type golf clubs out of metallic materials.These clubs were originally manufactured primarily by casting durablemetals such as stainless steel, aluminum, beryllium copper, etc. into aunitary structure comprising a metal body, face, and hosel. Astechnology progressed, it became more desirable to increase theperformance of the face of the club, usually by using a titaniummaterial.

With a high percentage of amateur golfers constantly searching for moredistance on their shots, particularly their drives, the golf industryhas responded by providing golf clubs specifically designed withdistance in mind. The head sizes of wood-type golf clubs have increased,allowing the club to possess a higher moment of inertia, whichtranslates to a greater ability to resist twisting on off-center hits.As a wood-type club head becomes larger, its center of gravity will bemoved back away from the face and further toward the toe, resulting inhits flying higher and further to the right than expected (forright-handed golfers). Reducing the lofts of the larger head clubs cancompensate for this. Because the center of gravity is moved further awayfrom hosel axis, the larger heads can also cause these clubs to remainopen on contact, thereby inducing a “slice” effect (in the case of aright-handed golfer the ball deviates to the right). Offsetting the headand/or incorporating a hook face angle can help compensate for this by“squaring” the face at impact, but often more is required to eliminatethe “slice” tendency.

Another technological breakthrough in recent years to provide theaverage golfer with more distance is to make larger head clubs whilekeeping the weight constant or even lighter by casting consistentlythinner shell thicknesses and using lighter materials such as titanium,magnesium, and composites. Also, the faces of the clubs have beensteadily becoming extremely thin, because a thinner face will maximizewhat is known as the Coefficient of Restitution (COR). The more a facerebounds upon impact, the more energy is imparted to the ball, therebyincreasing the resulting shot distance.

Known methods to enhance the weight distribution of wood-type club headsto help reduce the club from being open upon contact with the ballusually include the addition of weights to the body casting itself orstrategically adding a weight element at some point in the club. Manyefforts have been made to incorporate weight elements into the wood-typeclub head. These weight elements are usually placed at specificlocations, which will have a positive influence on the flight of theball or to overcome a particular golfer's shortcomings. As previouslystated, a major problem area of the higher handicap golfer is thetendency to “slice,” which in addition to deviating the ball to theright also imparts a greater spin to the ball, further reducing theoverall shot distance. To reduce this tendency, the present patentteaches the placement of weight elements directly into the club head.The placement of weight elements is designed so that the spin of theball will be reduced, and also a “draw” (a right-to-left ball flight fora right-handed golfer) will be imparted to the ball flight. This ballflight pattern is also designed to help the distance-challenged golferbecause a ball with a lower spin rate will generally roll a greaterdistance after initially contacting the ground than would a ball with agreater spin rate.

SUMMARY OF THE INVENTION

The present invention relates to a large wood-type golf club head withimproved playing characteristics. The club head may be formed of aplurality of body members that define an interior volume. A first bodymember is made of a metallic material and includes a sole portion and aface portion. A second body portion is made of a light-weight material,such as plastic, composite, or a very thin sheet of low density metallicmaterial. The second body portion makes up at least a portion of theclub head skirt, and includes one or more concave indentations thatextends into the interior volume of the club head. These indentationsprovide structural integrity to the second body portions, which may bevery thin panels.

The second body member optionally may also include one or more convexbulges that generally extend away from the interior volume. Inserts,such as weight inserts, may be positioned within the convex bulges.Careful positioning of the weight inserts allows the designer to enhancethe playing characteristics of the golf club and tailor the club for aspecific swing type. The first body member may form a large portion ofthe club head sole, and the second body member may form a large portionof the club head crown. This weight positioning further enhances theplaying characteristics of the golf club. The club head may includesecondary weights positioned extremely low and back from the strikingface. A center point on the sole plate defines the lowest point on theclub head, and in one embodiment the center point is located directlybelow the club head center of gravity when the club head is at a 59° lieangle. The center of gravity of the secondary weights are positioned apredetermined distance from the center point. Preferably, each secondaryweight center of gravity is at least 0.5 inch rearward of the centerpoint, at least 0.75 inch from the center point toward the heel for theheel weight or at least 0.75 inch from the center point toward the toefor the toe weight, and a maximum 0.25 inch above the center point,whereby the positions of the secondary weights alter the traditionallook of the golf club head by bulging outward of the natural contour ofthe club head.

The secondary weights may be located by reference to a point at whichthe hosel centerline intersects the sole plate. This distance is thenmeasured from the back surface of the striking face at the midpointthereof to determine an intersection point. Preferably, the secondaryweights are each at least 1.50 inches rearward of the intersectionpoint, at least 0.75 inch toward either the heel or the toe, and amaximum of 0.25 inch above the center point with the club head at a 59°lie angle.

The club head may include an inventive combination of geometric andphysical features. For example, the club head may have a large strikingsurface area, a large face length, and/or a large face height.Increasing the size of the striking face increases the sweet spot,making the golf club more forgiving and, therefore, more playable.

The club head may have a large depth, measured in a face-to-reardirection. Increasing the club head depth moves the center of gravityrearward, which also makes the club head more playable. This aspect ofthe invention may be quantified in a variety of manners, such as crownsurface area. Preferably, the golf club head has a large crown surfacearea. To further enhance these beneficial attributes, the crown may besloped from the striking face rearward, with at least a portion of thecrown being below the club head center of gravity. Preferably, asubstantial portion of the crown periphery is located below (on a soleside) the club head center of gravity.

The club head may be formed in a variety of manners. One such manner isby co-molding, a manufacturing process in which two dissimilar materialsare joined directly together by molding one of the materials to theother. For example, a metallic portion of the club head can form atleast part of a mold used to form a second portion of the club head froma light-weight material such as plastic or a composite material. Othermold pieces may also be used in conjunction with the metallic portion ofthe club head. Co-molding eliminates the need for welding or adhesives.The club head designer is free to use the mass that would have beentaken up by these known attachment means in other, more beneficial wayswithout increasing the overall mass of the club head. Such beneficialuses of the “freed-up” mass include increasing the overall size of theclub head, expanding the size of the club head sweet spot, repositioningthe club head center of gravity, and/or producing a greater moment ofinertia.

DESCRIPTION OF THE DRAWINGS

The present invention is described with reference to the accompanyingdrawings, in which like reference characters reference like elements,and wherein:

FIG. 1 shows a golf club head of the present invention;

FIG. 2 shows a body member of the golf club head of FIG. 1;

FIG. 3 shows a second club head of the present invention;

FIG. 4 shows a bottom view of the club head of FIG. 3;

FIG. 5 shows a bottom perspective view of a club head of the presentinvention;

FIG. 6 shows a rear elevation view of the club head of FIG. 5;

FIG. 7 shows a heel elevation view of the club head of FIG. 5;

FIG. 8 shows a bottom schematic view of the club head of FIG. 5;

FIG. 9 shows a front cross-sectional view of the club head of FIG. 5;

FIG. 10 shows a bottom view of a golf club head of the presentinvention;

FIG. 11 shows a bottom view of a golf club head of the presentinvention;

FIG. 12 shows a cross-sectional view of the club head of FIG. 11 takenalong line 12-12;

FIG. 13 shows a front view of a golf club head of the present invention;

FIG. 14 shows a top view of the golf club head of FIG. 13;

FIG. 15 shows a rear view of a golf club head of the present inventionwith the crown removed;

FIG. 16 shows a heel view of the golf club head of FIG. 15;

FIG. 17 shows a top view of the golf club head of FIG. 15 with the crownin place; and

FIG. 18 shows a front view of a golf club head of the present inventionand three cross-sectional views therethrough.

DETAILED DESCRIPTION OF THE INVENTION

Other than in the operating examples, or unless otherwise expresslyspecified, all of the numerical ranges, amounts, values and percentagessuch as those for amounts of materials, moments of inertias, center ofgravity locations, loft and draft angles, and others in the followingportion of the specification may be read as if prefaced by the word“about” even though the term “about” may not expressly appear with thevalue, amount, or range. Accordingly, unless indicated to the contrary,the numerical parameters set forth in the following specification andattached claims are approximations that may vary depending upon thedesired properties sought to be obtained by the present invention. Atthe very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claims, each numericalparameter should at least be construed in light of the number ofreported significant digits and by applying ordinary roundingtechniques.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Furthermore, when numerical ranges ofvarying scope are set forth herein, it is contemplated that anycombination of these values inclusive of the recited values may be used.

FIG. 1 shows a golf club head 1 of the present invention. The club head1 includes a body 10 having a strike face 11, a sole 12, a crown 13, askirt 14, and a hosel 15. The body 10 defines a hollow, interior volume16. Foam or other material may partially or completely fill the interiorvolume 16. Weights may optionally be included within the interior volume16. The face 11 may be provided with grooves or score lines therein ofvarying design. The club head 1 has a toe T and a heel H.

In this illustrated embodiment of FIG. 1, the club head 1 is comprisedof a plurality of body members that cooperatively define the interiorvolume 16. A first body member 101 includes a sole portion and a faceportion. The first body member 101 may include a complete to face 11 andsole 12. Alternatively, either or both the face 11 and the sole 12 canbe inserts coupled to the first body member 101. The club head 1 alsoincludes at least one second body member 102 coupled to the first bodymember 101 along the skirt 14 in known fashion. The crown 13 can beunitarily a portion of either body member 101, 102 or it may be aninsert coupled to either of the body members 101, 102. The second bodymember 102 includes a concave portion 20 that, when the body members101, 102 are coupled together, extends inward into the interior volume16. FIG. 2 shows an isolated view of an exemplary second body member102.

The first body member 101 preferably is formed of a metallic materialsuch as stainless steel, aluminum, or titanium. The material of thefirst body member 101 is chosen such that it can withstand the stressesand strains incurred during a golf swing, including those generatedthrough striking a golf ball or the ground. The club head 1 can beengineered to create a primary load bearing structure that canrepeatedly withstand such forces. Other portions of the club head 1,such as the skirt 14, experience a reduced level of stress and strainand advantageously can be replaced with a lighter, weight-efficientsecondary material. Lighter weight materials, such as low density metalalloys, plastic, composite, and the like, which have a lower density orequivalent density than the previously mentioned metallic materials, canbe used in these areas, beneficially allowing the club head designer toredistribute the “saved” weight or mass to other, more beneficiallocations of the club head 1. These portions of the club head 1 can alsobe made thinner, enhancing the weight savings. Exemplary uses for thisredistributed weight include increasing the overall size of the clubhead 1, expanding the size of the club head “sweet spot,” which is aterm that refers to the area of the face 11 that results in a desirablegolf shot upon striking a golf ball, repositioning the club head 1center of gravity, and/or producing a greater moment of inertia (MOI).Inertia is a property of matter by which a body remains at rest or inuniform motion unless acted upon by some external force. MOI is ameasure of the resistance of a body to angular acceleration about agiven axis, and is equal to the sum of the products of each element ofmass in the body and the square of the element's distance from the axis.Thus, as the distance from the axis increases, the MOI increases, makingthe club more forgiving for off-center hits since less energy is lostduring impact from club head twisting. Moving or rearranging mass to theclub head perimeter enlarges the sweet spot and produces a moreforgiving club. Increasing the club head size and moving as much mass aspossible to the extreme outermost areas of the club head 1, such as theheel H, the toe T, or the sole 12, maximizes the opportunity to enlargethe sweet spot or produce a greater MOI, making the golf club hotter andmore forgiving.

The second body member 102 is light-weight, which gives the opportunityto displace the club head center of gravity downward and to free weightfor more beneficial placement elsewhere without increasing the overallweight of the club head 1. When the wall thickness of the second bodymember 102 is at the minimum range of the preferred thickness, areinforcing body layer can be added in the critical areas in case themember shows deformations. These benefits can be further enhanced bymaking the second body member 102 thin. To ensure that the structuralintegrity of the club head 1 is maintained, these thin panels maypreferably include a concave portion 20. Inclusion of these concaveportions 20 allow the second body member 102 to withstand greaterstress—both longitudinally and transversely—without sustaining permanentdeformation or affecting the original cosmetic condition, ensuring thestructural integrity of the club head 1 is maintained. Preferredthicknesses for the first body member 101 include from 0.03 inch to 0.05inch, while preferred thicknesses for the second body member 102 includefrom 0.015 inch to 0.025 inch. Preferably, the concave portion 20displaces at least 10 cubic centimeters. More preferably, the concaveportion 20 displaces at least 25 cubic centimeters. While the club head1 can be virtually any size, preferably it is a legal club head. Aplurality of concave portions 20 may be used with the club head 1. Forexample, concave portions 20 of uniform or varying size may bepositioned in the toe, heel, back, etc.

FIG. 3 shows a cross-sectional view taken substantially perpendicular tothe face 11 of a second club head 2 of the present invention, and FIG. 4shows a bottom view of the club head 2. In the illustration of thisembodiment, the concave portion 20 is positioned at the back of the clubhead 2. The concave portion 20 preferably is not visible to the golferat address. In addition to the concave portion 20, the second bodymember 102 further includes a convex bulge 22 that extends generallyaway from the interior volume 16. An insert 23 may be positioned withinthe convex bulge. The insert 23 is not visible from outside the clubhead 2, and is thus illustrated using broken lines. In a preferredembodiment, the insert 23 is a weight insert. The convex nature of thebulge 23 allows the weight to be positioned to maximize the mechanicaladvantage it lends to the club head 2. As shown in FIG. 4, the club head2 may include a plurality of convex bulges 22, such as on a heel sideand on a toe side of the club head 2. The club designer may placeinserts 23 as desired within the bulges 22. The masses of the insertsmay be substantially equal. Alternatively, one of the inserts may have agreater mass than the other. This may be beneficial to design the clubto correct a hook swing or a slice swing. A preferred mass range for theweight insert 23 is from 1 gram to 50 grams.

As shown in FIG. 3, the first body member 101 may comprise a majority ofthe sole 12 and the second body member 102 may include a majority of thecrown 13. This beneficially removes a large majority of the mass fromthe upper part of the club head 2. In this embodiment the first bodymember 101 includes an attachment perimeter 18 that extends around itsedge.

The second body member 102 is coupled to the first body member 101 alongthe attachment perimeter 18. The first and second body members 101, 102cooperatively define the interior volume 16. The attachment perimeter 18preferably may contain a step defining two attachment surfaces 18 a, 18b. As illustrated, the second body member 102 may be coupled to both ofthese surfaces 18 a, 18 b to help ensure a strong bond between the bodymembers 101, 102.

While the body members 101, 102 may be formed in a variety of manners, apreferred manner includes forming a complete club head shell (first bodymember 101) in known manner and removing material to create openings towhich the second body member 102 can be coupled. The opening may becreated in any desired manner, such as with a laser. The second bodymember 102 may be joined to the first body member 101 in a variety ofmanners, such as through bonding or through a snap-fit in conjunctionwith bonding. If a composite material is used for the concave inserts,molding six plies of 0/90/45/-45/90/0 is preferred.

FIGS. 5-9 illustrate additional aspects of the present invention. In theembodiment illustrated in these figures, the club head 1 includes acrown portion 13, a sole 12, a heel portion H, a toe portion T, a skirtportion 14 connecting the heel portion H to the toe portion T, a frontface 11 and a hosel 24 that extends from the heel portion H. The clubhead 1 can be formed from sheets joined together, such as by welding, orcast, preferably from a titanium alloy. The crown portion 13 can be madefrom such materials as carbon fiber composite, polypropylene, Kevlar,magnesium, or a thermoplastic. Hosel 24 includes a bore defining acenterline axis C/L.

As best depicted in FIG. 9, the club head 1 of the present invention hasa center of gravity G located at an extremely rearward and low position.The location of the center of gravity G is biased by the location of twosecondary weights, a toe secondary weight 26 and a heel secondary weight28, which are both partially outside the traditional look of a golf clubhead. As shown in FIGS. 5-9, the locations of the two secondary weightelements 26, 28 are established by the relationship of their distancesfrom established points of contact. When the club head is at a lie angleφ of 59°, the lowest contact point of the sole 12 is at a center point Cdirectly beneath the center of gravity G.

One method of establishing the locations of the secondary weights 26, 28is discussed herein. As shown in FIG. 8, the center line C/L of hosel 24intersects the sole plate 12 at a distance D from the rear surface ofthe front face 11. When extending a line B-B that is substantiallyparallel to the leading edge of the club head (maintaining the distanceD), an intersection point P is made with a line A-A that isperpendicular to and extends rearward from the midpoint of the frontface 11. The line A-A extends through the middle of the club head 1 andpasses directly beneath the club head center of gravity G. Thisintersection point P may also be defined by the intersection of line A-Aand a vertical plane positioned at an intersection of the hosel centerline C/L and the sole 12. The center of gravity C/G of each secondaryweight 26, 28 is at a distance W of at least 1.50 inches rearward of theintersection point P, a distance Z that is a maximum of 0.25 inch abovethe lowest point of contact, which is the center point C of the soleplate 12, and each secondary weight is at least 0.75 inch away from lineA-A in opposing directions, which is a distance Y1 towards the toe T forthe toe secondary weight 26 and a distance Y2 towards the heel H for theheel secondary weight 28.

The locations of the secondary weights 26, 28 may also be determined forthe present invention by measuring from the center point C. From centerpoint C, the center of gravity of each secondary weight 26, 28 is adistance X of at least 0.50 inch rearward along line A-A, the distance Zthat is a maximum of 0.25 inch above the center point C, and a minimumof 0.75 inch away from line A-A in opposing directions, towards the toeT for the toe secondary weight 26 and towards the heel H for the heelsecondary weight 28. Thus, each secondary weight 26, 28 is a minimum of0.90 inch from the center point C.

The secondary weights 26, 28 can be selected from a plurality of weightsdesigned to make specific adjustments to the club head weight. Thesecondary weights 26, 28 can be welded into place or attached by abonding agent. The weights 26, 28 can be formed from typically heavyweight inserts such as steel, nickel, or tungsten. Preferably, the bodyof the club head 1 is formed from titanium, and the crown portion 13from a light-weight material such as carbon fiber composite,polypropylene, Kevlar, thermoplastic, magnesium, or some other suitablelight-weight material. Preferred volumes of the club head 1 include from350 cc to 460 cc. The secondary weights 26, 28 preferably range in massfrom 2 to 35 grams, with 10 grams to 35 grams being more preferred. Itis well known that by varying parameters such as shaft flex points,weights and stiffness, face angles, and club lofts, it is possible toaccommodate a wide spectrum of golfers. But the present inventionaddresses the most important launch consideration, which is to optimizethe club head mass properties (center of gravity and moment of inertia)by creating a center of gravity that is low, rearward, and wide ofcenter. The club head 1 of the present invention encompasses areas ofthe club head that are not typically utilized for weighting because theyadversely alter the traditional look of a club head. The design of thisclub head 1 allows for a portion of the secondary weights 26, 28 tobulge outside the normal contour of the club head.

FIG. 10 shows a bottom view of a golf club head 1 of the presentinvention. The skirt 14 includes an opening 30 towards the rear of theclub head 1. An insert 35 is positioned within the opening 30 in knownfashion, such as via an attachment perimeter 18, to cooperatively definethe interior volume 16. Preferably, the insert 35 is formed of alight-weight material such as a composite material or a polymermaterial. Using a light-weight insert 35 inherently biases the club headmass toward the sole 12 of the club head 1. It also allows the inclusionof a weight member to achieve a specific moment of inertia and/or centerof gravity location while maintaining typical values for the overallclub head weight and mass.

FIG. 11 shows a bottom view of a golf club head 1 of the presentinvention. In addition to secondary weights 26, 28, the club head 1includes an insert 27 intermediate the toe secondary weight 26 and theheel secondary weight 28. The insert 27 may be a weight insert similarto the toe and heel secondary weights 26, 28, in which case it also hasa preferable mass range of 2 to 35 grams. Alternatively, or in additionto being a weight member, insert 27 may include one or more indicia,such as a model or manufacturer designation. The club head 1 furtherincludes a sole insert 105; in the illustrated embodiment, two such soleinserts 105 are shown. These inserts 105 preferably are formed of alight-weight material as described above. Such materials likely arerobust enough to withstand contact with the ground such as the sole 12incurs through normal use of the golf club. However, the arcuate shapeof the sole 12 in the illustrated embodiment minimizes the likelihood ofthe inserts 105 contacting the ground. Inclusion of the sole inserts 105frees even more mass for more beneficial placement in the club head,such as at toe insert 26, intermediate insert 27, and/or heel insert 28.The location of the inserts 105 toward the center of the sole 12inherently biases the mass toward the outer portions of the club head 1,improving the club head MOI.

FIG. 12 shows a cross-sectional view of the club head 1 of FIG. 11 takenalong line 12-12. Here it is seen that the crown 13 is an insert that iscoupled to the metallic first body member 101. The crown insert 13preferably is formed of a light-weight material, beneficially displacingthe club head center of gravity downward and freeing yet more weight formore beneficial placement elsewhere without increasing the overallweight of the club head 1. Due to the inclusion of holes in which toposition the crown insert 13, the skirt insert 35, the second bodymember inserts 102, and the sole inserts 105, the first body member 101takes on the appearance of a frame. It should be noted that not everyinsert 13, 35, 102, 105 need be included in a particular embodiment ofthe present invention, though all may be present. The frame-like natureof first body member 101 is a load bearing structure that ensures thatthe stresses and strains incurred during a golf swing, including thosegenerated through striking a golf ball or the ground, do notdetrimentally affect the light-weight portions of the club head 1, whichexperience a reduced level of stress and strain. These club headportions, which may include secondary body member 102, crown 13, skirtinsert 35, and sole inserts 105, advantageously can be formed of alighter, weight-efficient secondary material such as low density metalalloys, plastics, composites, and the like, which have a lower densityor equivalent density than the previously mentioned metallic materials,beneficially allowing the club head designer to redistribute the “saved”weight or mass to other, more beneficial locations of the club head 1.These portions of the club head 1 can also be made thinner, enhancingthe weight savings.

The first body member 101 preferably includes an attachment perimeter 18for each insert (including the crown 13). These attachment perimeters 18extend around the edge of the respective openings. Preferably, eachattachment perimeter 18 includes a step defining two attachment surfaces18 a, 18 b, which provide additional assurance of a strong bond betweenthe respective club head components. (While each attachment perimeter 18of FIG. 12 includes a step defining two attachment surfaces 18 a, 18 b,such attachment surfaces 18 a, 18 b are called-out in only one locationfor the sake of clarity.)

The openings in the club head 1 into which the inserts 13, 35, 102, 105are positioned preferably may be created by forming a complete club headshell in known fashion, and then creating the openings therein. Onepreferred method of creating the openings is by using a laser to removeportions of the metallic material of the first body member 101. Thismethod provides for tight tolerances. The attachment perimeter 18,including attachment surfaces 18 a, 18 b, may be formed in a variety ofmanners, such as machining the first body member 101 after laser cuttingthe opening in the club head 1.

Alternatively to using adhesives and attachment surfaces 18 a, 18 b, thelight-weight inserts 13, 35, 102, 105 may be coupled to the club head 1by co-molding. The process of co-molding allows the insert(s) to beretained in place and coupled to the club head 1 without the need forattachment surfaces and adhesives, welding, etc. Exclusion of thesetraditional joining materials and structures frees more mass to bepositioned in more beneficial locations in the club head 1. The clubhead designer is free to position the mass that would have been consumedby the attachment surfaces and the attachment media (adhesive, epoxy,weld bead, mechanical fastener, etc.) as desired to, for example,beneficially position the club head center of gravity, achieve a desiredcenter of gravity location, achieve desired moment of inertiaproperties, increase the club head size, increase the club head sweetspot, etc., without increasing the overall weight of the club head.

This co-molding process may be performed in a variety of manners. In onesuch manner, an initial club head body is formed in known fashion. Theinitial club head body preferably includes one or more cavities orrecesses. See, for example, opening 30 in FIG. 10. Thereafter, theinitial club head body is placed within a mold. Liquid material is theninserted into the mold, filling or at least contacting the opening 30.Of course, the interior of the mold is shaped to impart the desiredshape to the finished club head. The initial club head and moldingmaterial is retained within the mold for the necessary amount of timeand subjected to the requisite thermal cycle(s), if appropriate for thematerials used. In this manner, the light-weight molding material isaffixed directly to the metallic (or other) material of the club headbody. The club head, with the insert 35 intact, is then removed from themold. Alternatively, plies of composite material, or other light-weightmaterial, can be used instead of a liquid molding material. The moldingtimes and temperatures will vary depending on the material(s) used, thethickness of the part(s) being formed, and other factors known to theskilled artisan. The mold may include other parts, such as an inflatablebladder, as desired by the club head designer. After the molding processis complete, or prior to the absolute completion of the molding process,as desired, the bladder is deflated and removed through a small hole inthe club head body, which hole is later filled in or covered. The moldmay also or alternatively be formed in part by mold pieces that arelater removed from the club head interior, such as through an opening inthe face that is later covered by an insert. It should be noted that themolded material need not contact the other (“major”) portion of the clubhead along the entire opening. Rather, the major body-minor body contactneed be only so much as is necessary to maintain mechanical andstructural integrity of the resulting golf club. This limited contactarea may be achieved, for example, through use of an inflatable bladder.Aspects of the invention discussed above, such as weights 23, 26, 28,can also be used with the co-molded sole 12.

In addition to reducing that amount and number of materials needed,co-molding also beneficially allows the use of materials nottraditionally used by golf club head designers. For example, atranslucent, plastic material may be used as the light-weight insertmaterial. The thickness of the molded material can also be reduced. Forexample, the thickness of the co-molded insert may be from 1 to 1.2 mm.The molded insert may have a varying thickness, such as by providing asmooth inner surface and a contoured outer surface or vice versa. If atranslucent material is used, the coloring and/or shading can be variedby varying the thickness of the insert.

Each sole insert 105 preferably has a mass of 0.5 gram to 10 grams, andmore preferably from 1 gram to 5 grams. The sole inserts 305, as well asthe other inserts, may be beveled or stepped slightly to provide alocation for any excess adhesive. In one embodiment, the toe and heelsole inserts 26, 28 each have a preferred mass range of 4 grams to 7grams, while the intermediate insert sole 27 has a preferred mass rangeof 2 grams to 3 grams. In one embodiment, the thickness of the club headcomponents is tapered such that the walls are thicker towards the face11 and thinner towards the rear of the club head 1. Such wall thicknesstapering frees more mass for more beneficial placement in the club head1.

In another aspect of the present invention, the face 11 is made to berelatively large. Providing a large face 11 increases the playabilityand forgiveness of the club head by, for example, increasing the size ofthe club head sweet spot and allowing for beneficial placement of weightmembers further away from the club head centerline. The governing bodiesof the rules of golf have deemed the maximum distance from the heel tothe toe of the club head to be 5 inches, and further that the maximumdistance from the sole to the crown of the club head to be 2.8 inches.Thus, in a preferred embodiment illustrated in FIGS. 13 and 14, the facehas a length FL (i.e., a measurement in the heel-toe direction along thewidest part of the face 11) of 5 inches and a height FH (i.e., ameasurement in the sole-crown direction along the tallest part of theface 11) of 2.8 inches. These dimensions may be slightly less to ensurecompliance with the rules. For example, the face length FL may be from4.5 to 5 inches, more preferably from 4.8 to 5 inches, and the faceheight FH may be from 2.5 to 2.8 inches, more preferably from 2.65 to2.8 inches. The dimensions of the face 11 may also be expressed as anaspect ratio, which is the ratio of the face length FL to the faceheight FH. The aspect ratio for the face 11 preferably is from 1.5 to 2,more preferably from 1.7 to 1.9. The face dimensions may also beexpressed as a measurement of the face surface area. Preferably, theface surface area is greater than 40 cm², more preferably greater than45 cm², and still more preferably greater than 50 cm². A preferred rangefor the face surface area is from 40 cm² to 60 cm². In one preferredembodiment, the face surface area is approximately 54 cm².

In addition to having a big face 11 (i.e., wide in the heel-toedimension (FL) and tall in the sole-crown dimension (FH)), the club head1 may also be long in the face-rear dimension. Providing a long clubhead body 10 moves the club head center of gravity rearward from theface, further increasing the playability of the resulting golf club.This also allows for beneficial placement of weights far behind the face11, and, in one embodiment, away from the club head centerline. Thegoverning bodies of the rules of golf have deemed that the distance fromthe heel to the toe of the club head must be greater than the distancefrom the face to the back. Thus, in a preferred embodiment, the clubhead depth HD is just less than the club face width. Preferreddimensions for the club head depth HD may be from 4.5 to 5 inches, morepreferably from 4.8 to 5 inches. Preferably, the club head depth HD iswithin 0.25 inch of the club head face length FL.

Preferably, the club head dimensions are measured on horizontal linesbetween vertical projections of the outermost points of:

-   -   the heel and the toe (dimension FL); and    -   the face and the back (dimension HD); and on vertical lines        between the horizontal projections of the outermost points of        the sole and the crown (dimension FH).

COR is an important characteristic of golf clubs, especially wood-typegolf clubs such as club head 1. COR is a measure of the efficiency ofthe transfer of energy between two colliding bodies, in this case thegolf club and the golf ball. As the efficiency of the energy transferincreases, the COR, the initial ball velocity, and the ball traveldistance increase. During a golf shot, the club face and the golf balldeform upon impact. The club face can deform and then recover more thanthe ball can. The ultimate aim of the dynamics or physics of thecollision is to limit the amount of deformation the ball sustainsbecause more energy is lost from a perfect collision due to heat, etc.in the ball. By allowing the strike face 11 to deform or deflect as muchas possible over a greater percentage of the face 11, a higherperformance strike face 11 can be constructed. As the amount of clubface deformation increases, so do the club head COR and the forcesapplied to the ball. The inventive large club head 1 preferably containsa large COR, for example 0.8 or greater, and more preferably 0.82 orgreater. One specific COR value that is preferred is 0.83, the maximumlimit allowed by the governing bodies of golf.

Due to the increased width (heel-to-toe) of the club face 11 and theincreased length (front-to-back) of the club head 1, the crown 13 has anincreased surface area. This crown surface area preferably is greaterthan 100 cm² or from approximately 100 cm² to 150 cm², and one exemplarycrown surface area is approximately 107 cm². Furthermore, a distance,substantially at the center of the club head 1, from the crown-faceintersection to the crown-skirt intersection at the rear of the clubhead is greater than 4 inches. More preferably, this distance is greaterthan 4.25 inches, and more preferably greater than 4.5 inches. Thisdistance may be measured as the trace along the crown in a verticalplane perpendicular to the club face 11 and, for example, passingthrough the geometric center of the club face 11.

As stated above, providing a properly balanced, large club head resultsin the club being more playable and forgiving. The club head 1preferably has a volume greater than 400 cm³. More preferably, this clubhead volume is greater than 425 cm³. Still more preferably, the clubhead volume is greater than 450 cm³. The governing bodies of the rulesof golf have deemed the club head must not exceed 460 cm³, with atolerance of 10 cm³. Thus, the club head volume should satisfy thelimitations imposed by the governing bodies.

To position the club head center of gravity toward the sole 12 and toincrease the club head MOI, which makes the club head 1 more forgivingand playable, the crown 13 of the club head 1 may have a unique design.According to this aspect of the invention, at least 35% of the club headouter periphery is positioned below the club head center of gravity. Asused here, outer periphery is defined as the arc length of the outermostarea of the crown 13. This aspect is illustrated in FIGS. 15-17. Turningfirst to FIG. 15, a rear view of the club head 1 (with the crown 13removed) is shown. A horizontal plane HP passing through the club headcenter of gravity CG is shown for reference purposes. As seen in FIG.16, which shows a heel view of the club head of FIG. 15, the club headbody 10 and the crown 13 (not shown) slope downward from the front tothe rear portions of the club head 1. FIG. 17 shows a top view of thegolf club head of FIG. 15 with the crown 13 in place. Due to the slopedcrown profile, a large portion of the crown 13 is below the club headcenter of gravity CG. The outer periphery of the crown 13 is comprisedof two arc lengths, A1 and A2. A1, which is illustrated in a heavy solidline in FIG. 17, indicates that portion of the crown outer peripherythat is above the club head center of gravity CG. A2, which isillustrated in a heavy dashed line in FIG. 17, indicates that portion ofthe crown outer periphery that is below the club head center of gravityCG. In the exemplary embodiment illustrated in FIG. 17, 35% of the crownouter periphery is below the club head center of gravity CG. In anotherpreferred embodiment, 40% of the crown outer periphery is below the clubhead center of gravity CG. In still another preferred embodiment, 45% ofthe crown outer periphery is below the club head center of gravity CG.In another preferred embodiment, the rear height of the club head 1 isless than or equal to 25% of the front height of the club head 1.

A structural or stiffening rib 40 to absorb and transmit stress andstrain generated during normal use of the resulting golf club may beprovided. One beneficial location for such a rib 40 is along a centralportion of the crown, with a curved, convex profile (when viewed fromabove the club head 1). As the rib 40 manages the brunt of the stressand strain generated during use of the golf club, other portions of thecrown 13 may be designed to enhance the playability of the golf club.For example, the crown 13 may contain concave dimples D₁, D₂. DimplesD₁, D₂ lower the crown profile, which in turn lowers the club headcenter of gravity. Preferred dimensions for the dimple D₁, which isbiased toward the club head toe, are: 2.9 to 3.5 inches for the depthDD₁, with 3 to 3.3 being more preferred; 2.2 to 2.6 inches for the widthDW₁, with 2.3 to 2.5 inches being more preferred. Preferred dimensionsfor the dimple D₂, which is biased toward the club head heel, are: 2.8to 3.4 inches for the depth DD₂, with 3.1 to 3.3 being more preferred;1.9 to 2.3 inches for the width DW₂, with 2 to 2.2 inches being morepreferred. Alternatively, the dimples D₁, D₂ can be identical. However,to achieve a properly balanced club head, in light of factors such asthe presence of the hosel 15 and the club head par area, the dimples D₁,D₂ may be of different size and dimension, as provided above.Preferably, the center of gravity height CGH, as measured from the sole12, is less than 1 inch. Alternatively, the center of gravity height CGHmay be from 0.7 to 1.1 inch, and more preferably 0.8 to 0.9 inch. Theseconcepts are illustrated in FIG. 18, which shows a front view of thegolf club head and three cross-sectional views. Section A-A is through acentral portion of the club head, section B-B is through a toe portionof the club head, and section C-C is through a heel portion of the clubhead.

To remove yet more weight from the upper portions of the club head, thecrown, or portions of the crown, can be provided in a light-weightmaterial, such as discussed with respect to the second body member 102above. The entire crown 13 may be formed of such light-weight material,or only portions of the crown, such as dimples D₁ and/or D₂ may beformed of light-weight material. It should be noted that “light-weightmaterial” includes thin portions of metal or other typically heavymaterial. The curved profile of the crown 13, described above, helps toensure that the structural integrity of the crown 13 is maintained.

The above-described club head attributes also impart a beneficial MOI tothe club head 1. Preferably, the club head 1 has a MOI about ahorizontal axis passing through the club head center of gravity of 260kg·mm² or greater, and a MOI about a vertical axis passing through theclub head center of gravity of 420 kg·mm² or greater. More preferablythese MOI values are 270 kg·mm² and 450 kg·mm², respectively. Still morepreferably MOI values are 280 kg·mm² and 470 kg·mm², respectively. Toprange MOI values may be 350 kg·mm² and 550 kg·mm², respectively.

The use of the terms “a” and “an” and “the” and similar references inthe context of describing the invention are to be construed to coverboth the singular and the plural, unless otherwise indicated herein orclearly contradicted by context. Recitation of ranges of values hereinare merely intended to serve as a shorthand method of referringindividually to each separate value falling within the range, unlessotherwise indicated herein, and each separate value is incorporated intothe specification as if it were individually recited herein.

As used herein, directional references such as rear, front, lower, etc.are made with respect to the club head when grounded at the addressposition. See, for example, FIG. 9. The direction references areincluded to facilitate comprehension of the inventive concepts disclosedherein, and should not be read as limiting.

While the preferred embodiments of the present invention have beendescribed above, it should be understood that they have been presentedby way of example only, and not of limitation. It will be apparent topersons skilled in the relevant art that various changes in form anddetail can be made therein without departing from the spirit and scopeof the invention. For example, while two body members have beendescribed above, the present invention may be embodied in a club headhaving more than two body members. Additionally, the present inventionmay be embodied in any type of club in addition to the wood-type clubsshown in the illustrated embodiments. Thus the present invention shouldnot be limited by the above-described exemplary embodiments, but shouldbe defined only in accordance with the following claims and theirequivalents. Furthermore, while certain advantages of the invention havebeen described herein, it is to be understood that not necessarily allsuch advantages may be achieved in accordance with any particularembodiment of the invention. Thus, for example, those skilled in the artwill recognize that the invention may be embodied or carried out in amanner that achieves or optimizes one advantage or group of advantagesas taught herein without necessarily achieving other advantages as maybe taught or suggested herein.

1-34. (canceled)
 35. A golf club head, comprising: a body comprising afirst material with a first density, the body having a striking face, asole, a crown, a heel, and a toe, wherein a portion of the sole consistsof the first material and further wherein the sole comprises a pluralityof sole inserts, each insert comprising a panel of a light-weightmaterial covering an opening through the first material andnon-threadably affixed to the first material at an attachment perimeterextending at least partly around the edge of the covered opening, suchthat each of sole inserts provides a portion of the sole and cooperateswith the remainder of the sole and body to define an interior volume ofthe club head, wherein the light-weight material has a density less thanthe first density.
 36. The club head of claim 35, further comprising: aheel weight located on a heel side of the club, a toe weight located ona toe side the club, each of the heel and toe weights having a seconddensity greater than the first density.
 37. The golf club head of claim35, wherein the heel and toe weights each have a mass from 2 grams to 35grams.
 38. The club head of claim 35, wherein the striking face has asurface area greater than 40 cm² and a width divided by a heightdefining an aspect ratio that is greater than 1.5, with the widthmeasured in a heel-toe direction and the height measured in a sole-crowndirection.
 39. The golf club head of claim 38, wherein the area isgreater than 50 cm².
 40. The golf club head of claim 38, wherein theaspect ratio is greater than 1.7.
 41. The golf club head of claim 35,wherein the crown has a surface area greater than 100 cm².
 42. The golfclub head of claim 35, wherein the crown further comprises an insertformed of a material selected from a group consisting of a composite, apolypropylenes, Kevlar, magnesium, a thermoplastic, a plastic, and alow-density metal alloys.
 43. The golf club head of claim 35, whereinthe light-weight material is selected from the group consisting of acomposite, a plastic, and a metal alloy.
 44. The club head of claim 35,wherein at least a majority of the sole consists of the first material45. The club head of claim 35, further comprising a center of gravitylocated a distance of approximately 1 inch or less above the sole. 46.The golf club head of claim 35, wherein the club head has a volumegreater than 400 cm³.
 47. The golf club head of claim 35, wherein adistance measured substantially at a center of the club head from acrown-face intersection to a rear edge of the crown is greater than 4inches.
 48. The golf club head of claim 47, wherein the distance isgreater than 4.25 inches.
 49. The club head of claim 36, furthercomprising an intermediate weight positioned between the heel and toeweights on the sole, the intermediate weight having a mass between 2 and35 grams.
 50. The club head of claim 36, wherein the plurality of soleinserts comprises two sole inserts, one located adjacent the heelweight, and the other located adjacent the toe weight.
 51. A golf clubhead, comprising: a body comprising a first material with a firstdensity, the body having a striking face, a sole, a crown, a heel, and atoe; and an insert comprising a panel of a light-weight materialcovering an opening through the first material and non-threadablyaffixed to the first material at an attachment perimeter extending atleast partly around the edge of the covered opening, such that theinsert provides a portion of the body and cooperates with the remainderof the body to define an interior volume of the club head, wherein thelight-weight material has a density less than the first density.
 52. Theclub head of claim 51, wherein the striking face has a surface areagreater than 40 cm² and—with a width measured in a heel-toe directionand a height measured in a sole-crown direction—the width divided by theheight defines an aspect ratio that is greater than 1.5, and furtherwherein the crown has a surface area greater than 100 cm².
 53. The golfclub head of claim 51, wherein at least a portion of the insert isformed of a material selected from the group consisting of a composite,polypropylene, Kevlar, magnesium, a thermoplastic, a plastic, a polymer,and a low-density metal alloys.
 54. The golf club head of claim 51,further comprising a first weight insert positioned on a toe side of thesole and a second weight insert positioned on a heel side of the sole,each of the first and second weight inserts having a mass from 2 gramsto 35 grams.